%%% On-line data for the M31 clusters (11 old + 6 luminous young) studied in 
 
    S. Perina, L. Federici, M. Bellazzini, C. Cacciari, F. Fusi Pecci, S. Galleti. 
    "HST/ACS colour-magnitude diagrams of M31 globular clusters", 2009A&A...507.1375 (P09)


 For each cluster are provided:

  - HST image (WFC/HRC, F606W, 20"x20")

  - astronomical coordinates and integrated magnitudes (P09, Tab.1 and Tab.2)

  - newly estimated parameters (P09, Tab.4 and Tab.6):
     R_hl   = half-light radius
     V_HB   = mean apparent V magnitude of the Horizontal branch
     E(B-V) = reddening
     mu_0   = distance modulus
     [Fe/H] = metallicity
     M_V_HB = integrated absolute V magnitude of the Horizontal branch
    
  - Color-Magnitude Diagram (old GCs: B,V or V,I; young GCs: F435W, F606W), 
    togheter with the CMD of a near surrounding field, for comparison

  - photometric catalogue, obtained with the Dolphot package 
    (Dolphin 2000 PASP 112,1383) applied to ACS (WFC/HRC) data



 - OBSERVATIONAL MATERIAL & REDUCTIONS

  HST ACS (WFC/HRC) archive data (see P09, Tab.1 for the old GCs, and Tab.2
  for the young GCs) were reduced with the ACS module of the Dolphot 
  package (Dolphin 2000 PASP 112,1383). The images were searched for sources
  having peak intensities greater than or equal to 3 SIGMA above the background.

  The output catalogues were cleaned by spurious and/or badly measured sources by
  selecting stars with: 
  
  HSTPHOT Global Quality Flag = 1
  Crowding parameter <= 0.3
  Chi sq.< 1.5 if V<22.5 and Chi sq. < 2.5 for brighter stars, for the old clusters
  Chi sq.< 1.5, for the young clusters
  |Sharpness| < 0.3


 - PHOTOMETRIC ERRORS

  The limiting magnitude of our photometry range from V~26 for the fields 
  observed with relatively short t_exp, to V~27.5 for deepest ones. The internal
  photometric errors of individual measures are in general within the range 
  0.01-0.08 mag for stars brighter than V=26, depending quite strongly on the
  degree of crowding. Errors increase rapidly for fainter stars, along with the 
  impact of blending.

 
 - PHOTOMETRIC SYSTEM

  DOLPHOT/ACS gives both VEGAMAG and Johnson-Cousin magnitudes (Sirianni 
  et al. 2005 PASP, 117, 1049).


 - OLD CLUSTERS PHOTOMETRIC CATALOGS 

   The photometric catalog of the 6 old clusters observed in the F435W, F606W bands
   holds: 
   
   n      = identification number
   x_px   = x coordinate in pixel   [1 WFC pixel = 0.05"; 1 HRC pixel = 0.028"]  
   y_px   = y coordinate in pixel   [1 WFC pixel = 0.05"; 1 HRC pixel = 0.025"]        
   B      = B magnitude        
   V      = V magnitude 
   F435W  = F435W magnitude 
   F606W  = F606W magnitude 
   eF435W = F435W mag. error
   eF606W = F606W mag. error
   chi^2  = chi^2 
   S/N    = signal-to-noise ratio
   sharp  = sharpness
   crowd  = crowding
   chip   = ACS camera (HRC=0; WFC1=1; WFC2=2)

   Similarly, the photometric catalog of the 5 old clusters observed in the F606W,
   F814W bands, holds: 
   
   n      = identification number
   x_px   = x coordinate in pixel   [1 WFC pixel = 0.05"; 1 HRC pixel = 0.028"]  
   y_px   = y coordinate in pixel   [1 WFC pixel = 0.05"; 1 HRC pixel = 0.025"]        
   V      = V magnitude 
   I      = I magnitude    
   F606W  = F606W magnitude 
   F814W  = F814W magnitude    
   eF606W = F606W mag. error
   eF814W = F814W mag. error
   chi^2  = chi^2 
   S/N    = signal-to-noise ratio
   sharp  = sharpness
   crowd  = crowding
   chip   = ACS camera (HRC=0; WFC1=1; WFC2=2)


 - YOUNG CLUSTERS PHOTOMETRIC CATALOGS

   Each catalog holds:
   
   n      = identification number
   x      = x coordinate (pixel)   [1 WFC pixel = 0.05"; 1 HRC pixel = 0.028"]  
   y      = y coordinate (pixel)   [1 WFC pixel = 0.05"; 1 HRC pixel = 0.025"]  
   B      = B magnitude
   V      = V magnitude  
   F435W  = F435W magnitude
   F606W  = F606W magnitude
   eF435W = F435W mag. error
   eF606W = F606W mag. error
   chi^2  = chi^2 
   S/N    = signal-to-noise ratio 
   sharp  = sharpness
   crowd  = dcrowding
   chip   = ACS camera (WFC1=1; WFC2=2)
  

 - ACKNOWLEDGMENTS

   If you use these data please acknowledge their source, i.e.

   Perina et al., 2009, A&A, 507, 1375 

 - CONTACTS

   sibilla.perina2@unibo.it
   luciana.federici@oabo.inaf.it
   michele.bellazzini@oabo.inaf.it